Forums > Stand Up Paddle Foiling

Foil too Large?

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Created by wind driven > 9 months ago, 8 May 2021
wind driven
NSW, 83 posts
8 May 2021 6:03PM
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I am a long time sup surfer and crossing over into sup foiling now. I have a Naish Jet 2000 front wing on. I am finding I am catching waves ok, coming up onto the foil but then often breaching or if too much front foot - nose diving. Is this part of the learning process or is the foil too big for me as a 70kg rider? Waves not huge or massively powerful.
Look forward to your thoughts on whether i just need to work on it more or i should go to a smaller front wing.

J_foil
NSW, 128 posts
8 May 2021 6:24PM
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Open disclosure, im not a sup foiler, only prone, but a common trait of either discipline is that between take off speed and foiling speed you will pass through the stall speed, at that point the center of lift moves forward and causes a tendancy for the nose to pitch up which could lead to a breach. I think with experience comes the ability to offset this with balance, and not an issue when you end up good enought to go from zero to foil speed quickly.

My feeling is 2000 is on the big side, but that might not be a bad thing when first starting out, just means you are up on foil at slower speeds. Perhaps try move the mast aft in the box and also get some flight time behind a boat so you can feel it out before you buy more gear.

Side note - as well as your own weight, foil size that feels good is relative to the speed of the waves you ride. 2000 might be spot on for (slow) wind swell, might feel too big when riding (faster) ground swell / deeper water waves.

Seajuice
NSW, 919 posts
8 May 2021 10:05PM
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Basically to big for your weight. But would be awesome if you get into wind wings.
I've found the best size foil is around 1600 cm for waist to shoulder high waves and 1200 for more powerful shoulder high to just overhead for my weight at 76 to 80kgs.
I'm sure you'll be pleasantly surprised if you go smaller if you find it hard to stop breaching.
But when you get good at riding you will probably control the big foil better as well. But it takes more effort.

foilthegreats
761 posts
8 May 2021 11:00PM
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I'm 75KG and did a large part of my prone foil learning on the Naish 2000 in extra small waves. I think it's a good wing to learn pumping on especially. Anything over waist high is gonna be challenging but doable. Fine tuning mast placement is key, good luck and have fun!

wind driven
NSW, 83 posts
9 May 2021 7:32PM
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Thank you all for your feedback, v useful input.
@Juzzy, I need to investigate the centre of lift principles as i had not really thought of it in these terms. I am familiar with Centre of Lateral resistance, centre of bouyancy, metacentric heights etc but centre of lift is a new one for me to try to understand.
@foilthe greats, what would your recommendation be on mast placement - towards back of track?
Thanks for all the feedback, I did actually buy the ring for wing foiling and but thats another thread...!

foilthegreats
761 posts
9 May 2021 11:13PM
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Select to expand quote
wind driven said..
Thank you all for your feedback, v useful input.
@Juzzy, I need to investigate the centre of lift principles as i had not really thought of it in these terms. I am familiar with Centre of Lateral resistance, centre of bouyancy, metacentric heights etc but centre of lift is a new one for me to try to understand.
@foilthe greats, what would your recommendation be on mast placement - towards back of track?
Thanks for all the feedback, I did actually buy the ring for wing foiling and but thats another thread...!


Start in the middle and adjust from there. Too much lift move mast back, too little lift move mast forward. It's always gonna be different depending on the board and foil used especially going from LA to HA foils. Another tip is only change 1 variable at a time.

Pacey
WA, 525 posts
10 May 2021 9:20AM
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Select to expand quote
Juzzy said..
Open disclosure, im not a sup foiler, only prone, but a common trait of either discipline is that between take off speed and foiling speed you will pass through the stall speed, at that point the center of lift moves forward and causes a tendancy for the nose to pitch up which could lead to a breach. I think with experience comes the ability to offset this with balance, and not an issue when you end up good enought to go from zero to foil speed quickly.

My feeling is 2000 is on the big side, but that might not be a bad thing when first starting out, just means you are up on foil at slower speeds. Perhaps try move the mast aft in the box and also get some flight time behind a boat so you can feel it out before you buy more gear.

Side note - as well as your own weight, foil size that feels good is relative to the speed of the waves you ride. 2000 might be spot on for (slow) wind swell, might feel too big when riding (faster) ground swell / deeper water waves.



How can stall speed be higher than take off speed? And why would the centre of lift move forward ar stall speed?

clayisland
20 posts
11 May 2021 2:11AM
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I agree with what's been said, foil is on the big side for your weight. I've surf foiled a 2400 and it's doable but feels big, smaller the waves the better.

There are so many pieces to learn to foil, that's why I made a learn to foil video course. Breaching involves many elements and it can be difficult to know which one to change.

One of the keys I find with sup foiling is foot placement, some kind of markers so I know exactly where my feet are and can make an adjustment on the next wave, or advanced foilers can adjust their feet on the fly.

J_foil
NSW, 128 posts
11 May 2021 7:50AM
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Select to expand quote
Pacey said..

Juzzy said..
Open disclosure, im not a sup foiler, only prone, but a common trait of either discipline is that between take off speed and foiling speed you will pass through the stall speed, at that point the center of lift moves forward and causes a tendancy for the nose to pitch up which could lead to a breach. I think with experience comes the ability to offset this with balance, and not an issue when you end up good enought to go from zero to foil speed quickly.

My feeling is 2000 is on the big side, but that might not be a bad thing when first starting out, just means you are up on foil at slower speeds. Perhaps try move the mast aft in the box and also get some flight time behind a boat so you can feel it out before you buy more gear.

Side note - as well as your own weight, foil size that feels good is relative to the speed of the waves you ride. 2000 might be spot on for (slow) wind swell, might feel too big when riding (faster) ground swell / deeper water waves.




How can stall speed be higher than take off speed? And why would the centre of lift move forward ar stall speed?


Perhaps my terminolgy is ****, as a surfer i mean the 'take off' starts at zero when you start paddling. As opposed to (say) lift off, when you start flying.

Im.not sure of the physics, i suppose the flow is attached near the front of the foil and detached near the rear.

Thinking about this some.more, probably the more pronounced influence is that the foil may be positioned so it is lifting you forward of the center of your bouyamcy/mass.center and.if you are not ready for it by becoming more front weighted as you accelerate, nose goes up = breach.

I know.for.sure that.on some.take.offs as the waves get faster as im.coming up on foil im almost totally on.my.front foot and just my back foot big toe is toching the tail. Once up and flying, weight is then even footed. Not suggesting thats good technique, but it gets it done.

mcrt
643 posts
11 May 2021 6:35AM
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IMHO water at slow speed flows around the foil like it does around a boat hull or any streamlined object.
It is not detached as in a stall, it does not create much lift (if any) because of the low speed and low angle of attack.
Lift increases with the square of speed so as soon as you drop in and accelerate it rises exponentially.

Water in a wave is rising up at different speeds and angles along the face,even submerged the foil has to push through a "ledge" at the right angle like non foil surfboards.
Maybe this is what you are feeling when dropping in in a steeper section?.

wind driven
NSW, 83 posts
13 May 2021 12:26PM
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Thank you very much everyone for your input on this, my takeaways are:
a. Invest in a smaller front foil
b. If not a. then put loads more weight on front foot as soon as I know i am on the wave
c. keep practicing!



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"Foil too Large?" started by wind driven